/**
* Returns a numeric value from the API.
* Works only for API methods that originally returns numeric values (there is no cast here)
*
* @param string $methodToCall Name of method to call, eg. Referers.getNumberOfDistinctSearchEngines
* @param bool|string $date A custom date to use when getting the value. If false, the 'date' query
* parameter is used.
*
* @return int|float
*/
protected function getNumericValue($methodToCall, $date = false)
{
$params = $date === false ? array() : array('date' => $date);
$return = Piwik_API_Request::processRequest($methodToCall, $params);
$columns = $return->getFirstRow()->getColumns();
return reset($columns);
}